Neil deGrasse Tyson (@neiltyson), astrophysicist, science communicator and author of the fantastic new book Astrophysics for People in a Hurry, joins Matt and Andy for a Definitely Science episode, discussing, well, the entire universe: Its origins, the forces that govern it, general relativity, the multiverse, dark matter, dark energy, the fact that the universe is under no obligation to make sense to you, and the questions that Neil would ask a physicist in the year 2317. This episode is brought to you by Parachute; visit parachutehome.com/science for free shipping and returns and a no-risk 60-night trial.

Matt and Andy traveled to downtown LA's Pershing Square and City Hall to take part in the March for Science, along the way speaking with various groups who had set up booths for the event, and even a neuroscientist listener who took the time to chat about her work giving cocaine to mice.

Don't forget that Probably Science (and Andy and Matt individually) will be performing live at Portland's Bridgetown Comedy Festival on May 7th. Get your festival passes now at bridgetowncomedy.com